Calculators have rapidly evolved relatively simple systems providing the basic four functions of addition, subtraction, multiplication and division into complex systems capable of providing trigonometric, logarithmic, exponential, and diverse other functions. Early calculator systems were implemented using a multiplicity of discrete integrated circuit packages. Later versions were more generally implemented in large scale integrated circuits until systems, such as disclosed in copending patent application, "Variable Function Calculator," Ser. No. 163,565, filed July 19, 1971, now abandoned and replaced by continuation application Ser. No. 420,999 filed Dec. 3, 1973, now abandoned, were implemented having all of the electronics on a single LSI chip. Thereafter, complexity increased and a plurality of LSI chips were utilized in systems, such as set forth in "Expandable Function Electronic Calculator," Ser. No. 444,226, filed Feb. 20, 1974, and its continuation-in-part, Ser. No. 607,525, filed May 16, 1973, now U.S. Pat. No. 3,984,816. Even more sophisticated systems were developed employing a plurality of large scale integrated circuit chips which efficiently allowed expanded data memory and program memory storage which allowed even the most sophisticated functions to be provided in a handheld calculator, such as described in detail in U.S. Pat. No. 3,900,722, and assigned to the assignee of this application.
Because of this evolution into sophisticated and complex machines, the operating instructions for these calculators have generally also become correspondingly sophisticated and complex. That is, the user of such a complex calculator generally must either frequently refer to an operating instructions guide which recites the particular sequence of inputs required by the systems, or the user must recall from his own memory the particular list before the calculator can be utilized to its fullest. The typical user would prefer not to have to carry along and refer to a user manual in order to effectively utilize the calculator.
Creating further difficulty for a user; beyond the complexity of its internal input sequence, a calculator may be of the type which allows the user thereof to store a desired program in the calculator in order to perform a particular series of functions. Such a user program may be entered from the calculator keyboard or may be read directly from a storage media such as magnetic cards or paper tapes. Once entered, the user program may be executed to provide instructions to the calculator system. In this manner, various stored functions are performed on data as it is being provided to the calculator through the keyboard. This data must be entered at the appropriate point in the operation of the program and in the proper sequence. For sophisticated programs prepared by the calculator manufacturer, a user's manual may be provided which indicates the proper sequence of data input, but this approach has all the disadvantages described above (because of the necessity of memorizing or constantly using such a manual). For programs written by the user himself, no such manual is available unless produced by the user. This tends to limit the effectiveness of user designed programs. Without proper inputs in a proper sequence, a calcualtor program is useless. While a calculator system has been described in detail in copending patent application, "Prompting Calculator," Ser. No. 439,473, filed Feb. 4, 1974, now U.S. Pat. No. 3,976,975 which provides prompting messages to the user in order to indicate what keyboard entry is next expected by the calculator's internally implemented functions, some such means indicating the next expected entry in a user-inserted program is needed.
It is therefore an object of the present invention to provide an improved user programmable electronic calculator system.
Another object of the invention is to provide an improved electronic calculator system which generates prompting messages indicative of information or data required by such calculator system in order to proceed with execution of a selected sequence of operations.
A still further object of the invention is to provide a user programmable calculator which generates prompting messages to the user.
Briefly, these and other objects and advantages are accomplished in accordance with the present invention, in which a user programmable calculator of the hand-held or desk-top variety is proviede with a prompting feature which allows the calculator to indicate to the user thereof the next keyboard input or sequence of inputs expected by the calculator for the particular program being executed. The calculator includes a keyboard, output display means and logic circuitry which generates to the output display means a prompting message indicating the type of numerical data, function or other responsive information which the program next requires for further execution. The keyboard includes a special set of response keys in addition to the numerical and functional keys normally incorporated on programmable calculator systems. The special keys facilitate responding to data and functional information requests by the calculator. The calculator may be programmed by the user to perform a series of functions upon data entries by entering a series or program steps from the keyboard or from a storage media such as a magnetic card, paper tape or the like. The program steps as well as the desired prompting messages are stored in binary form in registers of the calculator system provided therefor. Upon execution of the stored user program, each time numerical functional or responsive information is required a coded representation of the particular entry required for the calculator to proceed is generated by the logic circuitry and a visual indication thereof displayed to the user by the display means. The required data may then be entered from the keyboard and the program will continue executing until entry of further information is required from the user, thereby allowing the user to input in proper sequence a long series of inputs in order to execute a previously stored program on a desired set of data without referring to a manual or to the program itself.
In one embodiment, a multi-semiconductor chip calculator system which is comprised of one or more semiconductor chips providing conventional calculator functions is implemented so as to interface with additional chips providing increased data word and instruction word storage plus alphanumeric output capability. The increased instruction word storage allows a more sophisticated operating program to be utilized for implementing the prompting sequence. In a further embodiment, the basic chips are also capable of interfacing with further additional chips which provide storage and recall of sequences of user program instructions. In this further embodiment, a sequence of user program instructions may be entered from the calculator keyboard, or by utilizing an external semiconductor chip which allows reading and/or writing of a storage media such as a magnetic card or the like. The user program storage is extensive and allows alphanumeric prompting instructions to be included within the program. In an alternate embodiment, the storage and recall of sequences of user program instructions including the prompting messages is handled by the conventional calculator functions with the user program stored in the central memory of the system along with the data and other system parameters.